Three-dimensional imaging device and method, as well as program

ABSTRACT

Two or more images having a parallax therebetween are obtained by imaging a subject from different positions using imaging units. Three-dimensional processing for three-dimensional display is applied to the two or more images, and the two or more images are displayed on a display unit. While the imaging units carry out a zoom operation, three-dimensional display with a reduced parallax between the two or more images or two-dimensional display is performed.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.13/120,566 filed Mar. 23, 2011, which is a National Stage ofInternational Application PCT/JP2009/004458 filed Sep. 9, 2009, whichclaims priority to Japanese Application No. 2008-243825 filed Sep. 24,2008; the above-noted applications incorporated herein by reference intheir entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a three-dimensional imaging device anda three-dimensional imaging method for obtaining two or more images tobe used for three-dimensional display by imaging a subject fromdifferent positions, as well as a program for causing a computer tocarry out the three-dimensional imaging method.

2. Description of the Related Art

It has been known that stereoscopic viewing using a parallax can beachieved by combining two or more images and three-dimensionallydisplaying the combined images. Such stereoscopic viewing can beprovided by taking two or more images of the same subject from differentpositions using two or more cameras, and three-dimensionally displayingthe two or more images by using a parallax between the subject imagescontained in the images.

Specifically, if the stereoscopic viewing is achieved by parallelviewing with naked eyes, the three-dimensional display can be achievedby arranging the images side by side. Further, the three-dimensionaldisplay may be achieved by combining the images, for example, byoverlapping the images with providing the images with different colors,such as red and blue, or by overlapping the images with providing theimages with different polarization directions. In these cases, thestereoscopic viewing can be achieved by using image separating glasses,such as red-and-blue glasses or polarization glasses, to provide amerged view of the three-dimensionally displayed images, which isattained via the automatic focusing function of the eyes (anaglyphsystem, polarization filter system).

The stereoscopic viewing can also be achieved without using thepolarization glasses, or the like, by displaying the images on athree-dimensional display monitor which can provide stereoscopicviewing, such as a monitor of a parallax barrier system or a lenticularsystem. In this case, the three-dimensional display is achieved bycutting the images into vertical strips and alternately arranging thevertical strips of the images. Moreover, a system for providing thethree-dimensional display by alternately displaying left and rightimages with changing directions of light beams from the left and rightimages through the use of image separation glasses or by attaching anoptical element on the liquid crystal display has been proposed(scanning backlight system).

Further, stereoscopic cameras provided with two or more imaging units tocarry out imaging for the above-described three-dimensional display havebeen proposed. This type of stereoscopic camera includes two or moreimaging units disposed apart from each other by a predetermined distanceand generates an image for three-dimensional display from the imagesobtained by the two or more imaging units. The thus generated image forthree-dimensional display can be three-dimensionally displayed on amonitor. In addition, a method for use with this type of stereoscopiccamera for successfully providing stereoscopic viewing by changingpositions of the two or more images depending on a parallax levelbetween corresponding areas in the two or more images has been proposed(see Japanese Unexamined Patent Publication No. 8 (1996)-009421,hereinafter “Patent Document 1”).

In the case where imaging is carried out using the stereoscopic camera,a live view image is three-dimensionally displayed on the monitor beforethe release button is pressed. At this time, an angle of view to beimaged can be changed using a zoom function of each imaging unit. Inthis case, the photographer can image a subject at a desired size bymaking a zoom control operation on the stereoscopic camera while viewingthe three-dimensionally displayed live view image.

As described above, when the stereoscopic camera carries out a zoomoperation, the angle of view is changed. During the zoom operation, thesubject may often be out of focus. Further, since the stereoscopiccamera includes the two or more imaging units, the zoom operation iscarried out synchronously at the two or more imaging units. However, dueto individual variability of a motor and a mechanism for performing thezoom function at each imaging unit, it is very difficult to achievecompletely synchronous zoom operation at the imaging units. Thethree-dimensional display uses optical illusion to stereoscopicallydisplay the images. Therefore, when the zoom operation is carried outwhile the live view image is three-dimensionally displayed, the subjectmay be out of focus or the angle of view may vary at each imaging unit.Thus, during the zoom operation, the stereoscopic effect of thethree-dimensionally displayed image may change or the stereoscopiceffect may appear or disappear, and this makes it very hard to performstereoscopic viewing.

SUMMARY OF THE INVENTION

In view of the above-described circumstances, the present invention isdirected to alleviating uncomfortable feeling felt when stereoscopicviewing cannot be performed during a zoom operation when two or moreimages are taken for three-dimensional display.

A three-dimensional imaging device according to the invention includes:

two or more imaging means for obtaining two or more images having aparallax therebetween by imaging a subject from different positions, thetwo or more imaging means having an optical zoom function;

three-dimensional processing means for applying three-dimensionalprocessing for three-dimensional display to the two or more images;

display means for carrying out various types of display includingthree-dimensional display of the two or more images; and

display control means for carrying out three-dimensional display with areduced parallax between the two or more images or two-dimensionaldisplay while the imaging means carry out a zoom operation.

The “three-dimensional display with a reduced parallax” refers tothree-dimensional display carried out with reducing a stereoscopiceffect, which has been felt while the three-dimensionally displayedimage is viewed before the zoom operation, and the “two-dimensionaldisplay” refers to display with no stereoscopic effect, i.e., with noparallax.

In the three-dimensional imaging device according to the invention, thethree-dimensional processing means may carry out the three-dimensionalprocessing with a reduced parallax while the imaging means carry out thezoom operation.

The three-dimensional display with a reduced parallax or thetwo-dimensional display may be achieved by reducing a distance betweenthe two or more imaging means.

In the three-dimensional imaging device according to the invention, in acase where an object is three-dimensionally displayed with beingsuperposed on the three-dimensionally displayed image, the displaycontrol means may carry out three-dimensional display with a reducedparallax or two-dimensional display of the object while the imagingmeans carry out the zoom operation.

The object herein refers to an image displayed on the display meansother than images obtained through imaging. Specifically, examples ofthe object includes imaging conditions, such as F value and shutterspeed, the number of images taken and imaging time and date, iconsrepresenting modes, such as image stabilizing mode, flash on/off, personmode, etc., pictograms, and menus for various operations.

The three-dimensional imaging device according to the invention mayfurther include notification means for notifying that thethree-dimensional display with a reduced parallax or the two-dimensionaldisplay is being carried out.

In the three-dimensional imaging device according to the invention, thedisplay control means may gradually reduce the parallax after the zoomoperation is started until the parallax becomes 0 to finally carry outthe two-dimensional display.

In the three-dimensional imaging device according to the invention, thedisplay control means may gradually reduce the parallax after the zoomoperation is started until the parallax becomes a predetermined parallaxto finally carry out the three-dimensional display with a reducedparallax.

A three-dimensional imaging method according to the invention is athree-dimensional imaging method for use with a three-dimensionalimaging device including two or more imaging means for obtaining two ormore images having a parallax therebetween by imaging a subject fromdifferent positions, the two or more imaging means having an opticalzoom function, three-dimensional processing means for applyingthree-dimensional processing for three-dimensional display to the two ormore images, and display means for carrying out various types of displayincluding three-dimensional display of the two or more images, themethod including:

carrying out three-dimensional display with a reduced parallax betweenthe two or more images or two-dimensional display while the imagingmeans carry out a zoom operation.

The three-dimensional imaging method according to the invention may beprovided in the form of a program for causing a computer to carry outthe three-dimensional imaging method.

According to the invention, while the imaging means carryout the zoomoperation, the three-dimensional display with a reduced parallax betweenthe two or more images or the two-dimensional display is carried out.Therefore, when the photographer makes a zoom control operation, thestereoscopic effect of the three-dimensional display can be reduced. Inthis manner, even when stereoscopic viewing cannot be performed duringthe zoom operation, variation of the stereoscopic effect is smaller,thereby alleviating the uncomfortable feeling felt during the zoomoperation. In particular, by carrying out three-dimensional display withno stereoscopic effect by reducing the parallax to 0, i.e.,two-dimensional display, no variation of stereoscopic effect occursduring the zoom operation, thereby reliably alleviating theuncomfortable feeling felt during the zoom operation.

Further, by carrying out the three-dimensional processing with a reducedparallax while the imaging means carry out the zoom operation, thereduction of stereoscopic effect can be achieved without increasing thecomponents of the device, thereby preventing the device configurationfrom being complicated.

Furthermore, in the case where an object is three-dimensionallydisplayed with being superposed on the three-dimensionally displayedimage, the object may be three-dimensionally displayed with a reducedparallax or two-dimensionally displayed while the imaging means carryout the zoom operation. Thus, the stereoscopic effect of the object inthe three-dimensional display can be reduced when the photographer makesa zoom control operation. In this manner, even when stereoscopic viewingcannot be performed during the zoom operation, variation of thestereoscopic effect of the object is smaller, thereby alleviating theuncomfortable feeling felt during the zoom operation.

Moreover, by notifying that the three-dimensional display with a reducedparallax or the two-dimensional display is being carried out, thephotographer can recognize based on the notification that thethree-dimensional display with a reduced parallax or the two-dimensionaldisplay is being carried out.

In addition, by gradually reducing the parallax after the zoom operationis started until the parallax becomes 0 to finally carry out thetwo-dimensional display, or gradually reducing the parallax after thezoom operation is started until the parallax becomes a predeterminedparallax to finally carry out the three-dimensional display with areduced parallax, abrupt change of the stereoscopic effect when the zoomoperation is started can be prevented, thereby achieving furtheralleviation of the uncomfortable feeling.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram illustrating the internalconfiguration of a stereoscopic camera, to which a three-dimensionalimaging device according to an embodiment of the present invention isapplied,

FIG. 2 is a diagram illustrating the configuration of an imaging unit,

FIG. 3 is a diagram illustrating stereoscopic effects when display isswitched,

FIG. 4 is another diagram illustrating stereoscopic effects when displayis switched,

FIG. 5 is a flow chart illustrating a process carried out in theembodiment,

FIG. 6 is a diagram illustrating an image displayed with objectssuperposed thereon,

FIG. 7 is a diagram illustrating a state where a “2D” mark is displayed,

FIG. 8 is a diagram illustrating stereoscopic effects when display isswitched in a case where a reduced parallax is used,

FIG. 9 is another diagram illustrating stereoscopic effects when displayis switched in a case where a reduced parallax is used, and

FIG. 10 is a diagram for explaining changes of a baseline length and aconvergence angle of imaging units.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, an embodiment of the present invention will be describedwith reference to the drawings. FIG. 1 is a schematic block diagramillustrating the internal configuration of a stereoscopic camera, towhich a three-dimensional imaging device according to the embodiment ofthe invention is applied. As shown in FIG. 1, the stereoscopic camera 1according to this embodiment includes two imaging units 21A and 21B, animaging control unit 22, an image processing unit 23, acompression/decompression unit 24, a frame memory 25, a media controlunit 26, an internal memory 27, and a display control unit 28. Theimaging units 21A and 21B are positioned to be able to photograph asubject with a predetermined baseline length and a convergence angle.

FIG. 2 illustrates the configuration of the imaging units 21A and 21B.As shown in FIG. 2, the imaging units 21A and 21B include focusinglenses 10A and 10B, zoom lenses 11A and 11B, aperture diaphragms 12A and12B, shutters 13A and 13B, CCDs 14A and 14B, analog front ends (AFE) 15Aand 15B and A/D converting units 16A and 16B, respectively. The imagingunits 21A and 21B further include focusing lens driving units 17A and17B for driving the focusing lenses 10A and 10B and zoom lens drivingunits 18A and 18B for driving the zoom lenses 11A and 11B.

The focusing lenses 10A and 10B are used to focus on the subject, andare movable along the optical axis directions by the focusing lensdriving units 17A and 17B, each of which is formed by a motor and amotor driver. The focusing lens driving units 17A and 17B control themovement of the focusing lenses 10A and 10B based on focus data obtainedthrough AF processing, which will be described later, carried out by theimaging control unit 22.

The zoom lenses 11A and 11B are used to achieve a zoom function, and aremovable along the optical axis directions by the zoom lens driving units18A and 18B, each of which is formed by a motor and a motor driver. Thezoom lens driving units 18A and 18B control the movement of the zoomlenses 11A and 11B based on zoom data obtained at the CPU 33 uponoperation of a zoom lever.

Aperture diameters of the aperture diaphragms 12A and 12B are adjustedby an aperture diaphragm driving unit (not shown) based on aperturevalue data obtained through AE processing carried out by the imagingcontrol unit 22.

The shutters 13A and 13B are mechanical shutters, and are driven by ashutter driving unit (not shown) according to a shutter speed obtainedthrough the AE processing.

Each of the CCDs 14A and 14B includes a photoelectric surface, on whicha large number of light-receiving elements are arrangedtwo-dimensionally. Light from the subject is focused on eachphotoelectric surface and is subjected to photoelectric conversion toprovide an analog imaging signal. Further, a color filter formed byregularly arranged R, G and B color filters is disposed on the frontside of each CCD 14A, 14B.

The AFEs 15A and 15B process the analog imaging signals fed from theCCDs 14A and 14B to remove noise from the analog imaging signals andadjust gain of the analog imaging signals (this operation is hereinafterreferred to as “analog processing”).

The A/D converting units 16A and 16B convert the analog imaging signals,which have been subjected to the analog processing by the AFEs 15A and15B, into digital signals. The image represented by digital image dataobtained by the imaging unit 21A is referred to as a first image G1, andthe image represented by digital image data obtained by the imaging unit21B is referred to as a second image G2.

The imaging control unit 22 includes an AF processing unit and an AEprocessing unit (not shown). When a release button included in the inputunit 34 is half-pressed, the imaging units 21A and 21B obtainpreliminary images, and the AF processing unit determines focused areasand focal positions for the lenses 10A and 10B based on the preliminaryimages, and outputs them to the imaging units 21A and 21B. The AEprocessing unit determines an aperture value and a shutter speed basedon the preliminary images, and outputs them to the imaging units 21A and21B.

As the method used to detect the focal points through the AF processing,a passive method may be used, for example. In the passive method, thefocus position is detected based on characteristics that an imagecontaining a desired subject being focused has a higher contrast value.More specifically, each preliminary image is divided into a plurality ofAF areas, and an image in each AF area is filtered using a high-passfilter. Then, an AF evaluation value is calculated for each AF area, andthe AF area having the highest evaluation value, i.e., the highestoutput value from the filter, is detected as the focused area.

When the release button is fully pressed, the imaging control unit 22instructs the imaging units 21A and 21B to carry out actual imaging toobtain actual images of the first and second images G1 and G2. It shouldbe noted that, before the release button is operated, the imagingcontrol unit 22 instructs the imaging unit 21A to successively obtain alive view image, which has fewer pixels than the first and second imagesG1 and G2, at a predetermined time interval (for example, at an intervalof 1/30 seconds) for checking imaging range of the imaging unit 21A.

It should be noted that the imaging control unit 22 also carries out theAF processing while the live view image is taken. The AF processing inthis case is achieved by a simpler calculation than the AF processingbased on the preliminary images.

The image processing unit 23 applies image processing, such as whitebalance adjustment, tone correction, sharpness correction and colorcorrection, to the digital image data of the first and second images G1and G2 obtained by the imaging units 21A and 21B. In this description,the first and second images which have been processed by the imageprocessing unit 23 are also denoted by the same reference symbols G1 andG2 as the unprocessed first and second images.

The compression/decompression unit 24 applies compression processingaccording to a certain compression format, such as JPEG, to the imagedata representing an image for three-dimensional display, which isgenerated, as will be described later, from the actual images of thefirst and second images G1 and G2 processed by the image processing unit23, and generates a three-dimensional image file used forthree-dimensional display. The three-dimensional image file contains theimage data of the first and second images G1 and G2 and the image dataof the image for three-dimensional display. A tag storing associatedinformation, such as photographing time and date, is added to the imagefile based on the Exif format, or the like.

The frame memory 25 is a work memory used to carry out various types ofprocessing, including the above-described processing carried out by theimage processing unit 23, applied to the image data representing thefirst and second images G1 and G2 obtained by the imaging units 21A and21B.

The media control unit 26 accesses a recording medium 29 and controlswriting and reading of the three-dimensional image file, etc.

The internal memory 27 stores various constants to be set in thestereoscopic camera 1, a program executed by the CPU 33, etc.

The display control unit 28 causes the first and second images G1 and G2stored in the frame memory 25 during imaging to be two-dimensionallydisplayed on the monitor 20, or causes the first and second images G1and G2 recorded in the recording medium 29 to be two-dimensionallydisplayed on the monitor 20. The display control unit 28 is also able tocause the first and second images G1 and G2, which have been subjectedto the three-dimensional processing, as will be described later, to bethree-dimensionally displayed on the monitor 20, or to cause thethree-dimensional image file recorded in the recording medium 29 to bethree-dimensionally displayed on the monitor 20. Switching between thetwo-dimensional display and the three-dimensional display mayautomatically be carried out, or may be carried out according toinstructions from the photographer via the input unit 34, which will bedescribed later. During the three-dimensional display, a live view imageof the first and second images G1 and G2 is three-dimensionallydisplayed on the monitor 20 until the release button is pressed.

It should be noted that, when the display mode is switched tothree-dimensional display, both the first and second images G1 and G2are used for the display, as will be described later. In contrast, whenthe display mode is switched to two-dimensional display, one of thefirst and second images G1 and G2 is used for the display. In thisembodiment, the first image G1 is used for the two-dimensional display.

Further, when the imaging units 21A and 21B carryout the zoom operationduring three-dimensional display of the live view image, as will bedescribed later, the display control unit 28 switches the display totwo-dimensional display.

The stereoscopic camera 1 according to this embodiment further includesa three-dimensional processing unit 30. The three-dimensional processingunit 30 applies the three-dimensional processing to the first and secondimages G1 and G2 to allow three-dimensional display of the first andsecond images G1 and G2 on the monitor 20. The three-dimensional displaytechnique used in this embodiment may be any of known techniques. Forexample, the stereoscopic viewing may be achieved by parallel viewingwith naked eyes by displaying the first and second images G1 and G2 sideby side, or the three-dimensional display may be achieved using alenticular system, where a lenticular lens is attached on the monitor20, and the images G1 and G2 are displayed at predetermined positions onthe display surface of the monitor 20 so that the first and secondimages G1 and G2 are respectively viewed by the left and right eyes.Further, which the three-dimensional display may be achieved using ascanning backlight system, where optical paths of backlights of themonitor 20 are optically separated correspondingly to the left and righteyes in an alternate manner, and the first and second images G1 and G2are alternately displayed on the display surface of the monitor 20synchronously with the separation of the backlights to the left or theright.

The three-dimensional processing unit 30 applies the three-dimensionalprocessing depending on the type of three-dimensional display to thefirst and second images G1 and G2. For example, if the three-dimensionaldisplay is achieved by parallel viewing with naked eyes, thethree-dimensional processing is achieved by generating a stereoscopicimage by arranging the first and second images G1 and G2 side by side onthe left and right is carried out. If the three-dimensional display isachieved with a lenticular system, the three-dimensional processing isachieved by generating a stereoscopic image by cutting the first andsecond images G1 and G2 into vertical strips and alternately arrangingthe vertical strips of the images. If the three-dimensional display isachieved with a scanning backlight system, three-dimensional processingto alternately output the first and second images G1 and G2 to themonitor 20 synchronously with separation of backlights of the monitor 20to the left and right is carried out.

The monitor 20 is modified according to the type of thethree-dimensional processing carried out by the three-dimensionalprocessing unit 30. For example, if the system of the three-dimensionaldisplay is a lenticular system, a lenticular lens is attached on thedisplay surface of the monitor 20. If the system of thethree-dimensional display is a scanning backlight system, an opticalelement for changing directions of the light beams from the left andright images is attached on the display surface of the monitor 20.

In this embodiment, when the photographer makes a zoom control operationusing a zoom lever 34A while the live view image of the first and secondimages G1 and G2 is displayed, the imaging units 21A and 21B carryout azoom operation, and the display control unit switches the display fromthree-dimensional display to two-dimensional display. Specifically, inplace of the image for three-dimensional display generated by thethree-dimensional processing unit 30, the first image G1 is displayed onthe monitor 20. In this case, driving of the imaging unit 21B may bestopped so that only the imaging unit 21A images the subject to obtainthe first image G1. It should be noted that, at the three-dimensionalprocessing unit 30, an image for two-dimensional display may begenerated by morphing the first and second images G1 and G2 so that aparallax between subject images contained in the first and second imagesG1 and G2 becomes 0, and the thus generated image for two-dimensionaldisplay may be two-dimensionally displayed on the monitor 20. Further,when the imaging units 21A and 21B end the zoom operation, the displaycontrol unit 28 switches the display from two-dimensional display tothree-dimensional display. FIG. 3 is a diagram illustrating stereoscopiceffects when the display is switched. As shown in FIG. 3, when thephotographer starts the zoom control operation, the display is switchedfrom three-dimensional display to two-dimensional display and thestereoscopic effect becomes 0. Then, when the photographer finishes thezoom control operation, the display is switched from two-dimensionaldisplay to three-dimensional display and the stereoscopic effectappears.

It should be noted that switching of the display from three-dimensionaldisplay to two-dimensional display and from two-dimensional display tothree-dimensional display may be carried out such that the stereoscopiceffect is gradually changed. In this case, as shown in FIG. 4, when thephotographer starts the zoom control operation, the display is graduallyswitched from three-dimensional display to two-dimensional display, andthe stereoscopic effect gradually becomes 0. Then, when the photographerfinishes the zoom control operation, the display is gradually switchedfrom two-dimensional display to three-dimensional display, and thestereoscopic effect gradually appears.

Change of the stereoscopic effect when the display is switched fromthree-dimensional display to two-dimensional display may be achieved byapplying the three-dimensional processing to gradually reduce theparallax, i.e., an amount of disparity, between first and second imagesG1 and G2. In contrast, change of the stereoscopic effect when thedisplay is switched from two-dimensional display to three-dimensionaldisplay may be achieved by applying the three-dimensional processing togradually restore the original parallax, i.e., the original amount ofdisparity, between the first and second images G1 and G2.

In addition to changing the amount of disparity between the first andsecond images G1 and G2, gradual change of the stereoscopic effect maybe achieved by sequentially generating interpolation images from thefirst and second images G1 and G2 with using the first image G1 as areference such that the parallax between the subject images contained inthe first and second images G1 and G2 is gradually reduced, and carryingout, each time the interpolation image is generated, thethree-dimensional processing using the first image G1 and eachinterpolation image and display of the image for three-dimensionaldisplay generated through the three-dimensional processing.

The CPU 33 controls the units of the stereoscopic camera 1 according tosignals inputted via the input unit 34, which includes the releasebutton, etc.

The data bus 35 is connected to the units forming the stereoscopiccamera 1 and the CPU 33, and communicates various data and informationin the stereoscopic camera 1.

Next, a process carried out in this embodiment is described. FIG. 5 is aflow chart illustrating the process carried out in this embodiment. Itis assumed here that the live view image of the first and second imagesG1 and G2 is three-dimensionally displayed on the monitor 20 of thestereoscopic camera 1 through the three-dimensional processing appliedby the three-dimensional processing unit 30 to the first and secondimages G1 and G2 obtained by the imaging units 21A and 21B. Since theinvention is characterized by a process carried out during the zoomoperation of the imaging units 21A and 21B, only a process that iscarried out when the zoom control operation is made using the zoom lever34A while the live view image is displayed is described.

The CPU 33 monitors whether or not the photographer has operated thezoom lever 34A (step ST1). If the determination in step ST1 isaffirmative, the imaging units 21A and 21B start the zoom operation, andthe display control unit 28 switches the display to two-dimensionaldisplay where only the first image G1 is displayed on the monitor 20(step ST2). Then, the CPU 33 starts monitoring whether or not thephotographer has ended the zoom control operation (step ST3). If thedetermination in step ST3 is affirmative, the imaging units 21A and 21Bstop the zoom operation, and the imaging control unit 22 performs the AFprocessing of the imaging units 21A and 21B (step ST4).

Subsequently, the display control unit 28 switches the display on themonitor 20 to three-dimensional display of the live view image (stepST5), and the process returns.

Then, when the release button is pressed to carry out imaging, theimaging units 21A and 21B obtain the actual images of the first andsecond images G1 and G2. Then, the three-dimensional processing unit 30generates the image for three-dimensional display from the first andsecond images G1 and G2, the compression/decompression unit 24 generatesthe three-dimensional image file formed by image data of the first andsecond images G1 and G2 and the image for three-dimensional display, andthe media control unit 26 records the three-dimensional image file inthe recording medium 29.

As described above, in this embodiment, two-dimensional display iscarried out while the imaging units 21A and 21B carry out the zoomoperation. Therefore, no variation of the stereoscopic effect of theimage displayed on the monitor 20 occurs during the zoom operation,thereby reliably alleviating the uncomfortable feeling felt due tovariation of the stereoscopic effect during the zoom operation.

After the zoom operation is ended, the AF processing of the imagingunits 21A and 21B is carried out, and then the display is switched tothree-dimensional display. Therefore, the three-dimensional display iscarried out with the first and second images G1 and G2 being in focus.Thus, after the zoom operation is ended, stereoscopic viewing can beachieved successfully.

It should be noted that, in the above-described embodiment, while thelive view image is displayed, objects may be superposed on the image.FIG. 6 is a diagram illustrating an image displayed with objectssuperposed thereon. Here, a state where objects are superposed on atwo-dimensional image is shown for the purpose of explanation. As shownin FIG. 6, on the image displayed on the monitor 20, an object of anicon representing emission of flash light is superposed at theupper-left corner, an object of the number of images taken so far issuperposed at the upper-right corner, an object of an F value and ashutter speed is superposed at the lower-left corner, and an object of atext showing the photographing date is superposed at the lower-rightcorner.

In this case, the objects can be three-dimensionally displayed to allowstereoscopic viewing by arranging the objects on each of the first andsecond images G1 and G2 such that a parallax is provided therebetween.In the case where the objects are three-dimensionally displayed likethis, display of the objects may be switched from three-dimensionaldisplay to two-dimensional display while the imaging units 21A and 21Bcarry out the zoom operation, in the same manner as the first and secondimages G1 and G2. Thus, variation of the stereoscopic effect of theobjects becomes small, thereby alleviating the uncomfortable feelingfelt during the zoom operation.

Further, since stereoscopic viewing cannot be performed when the displayis switched from three-dimensional display to two-dimensional display inthe above-described embodiment, the photographer may misunderstand thisto be a failure of the device 1. Therefore, as shown in FIG. 7, thedisplay control unit 28 may display a “2D” mark M0 on the monitor 20 tonotify the photographer of the fact that two-dimensional display isbeing carried out. In this case, the display control unit 28 correspondsto a notification means. In this manner, the photographer can recognize,based on the mark M0, that two-dimensional display is being carried out.Alternatively, in place of displaying the mark M0, the device 1 may beprovided with a sound output unit to use a sound to notify thephotographer of the fact that two-dimensional display is being carriedout. Further alternatively, both the sound and display of the mark M0may be used to notify the photographer of the fact that two-dimensionaldisplay is being carried out.

Further, although the display is switched from three-dimensional displayto two-dimensional display when the photographer has started the zoomcontrol operation in the above-described embodiment, three-dimensionaldisplay with a smaller parallax may be carried out, in place of thetwo-dimensional display, by applying the three-dimensional processingwith a reduced parallax between the first and second images G1 and G2.

The three-dimensional processing with a reduced parallax can be achievedby reducing a parallax, i.e., an amount of disparity, between subjectimages contained in the first and second images G1 and G2. Thethree-dimensional processing with a reduced parallax can also beachieved by morphing the first and second images G1 and G2 using thefirst image G1 as a reference to generate an interpolation image with areduced parallax between subject images contained in the first andsecond images G1 and G2, and carrying out the three-dimensionalprocessing using the first image G1 and the interpolation image.

FIG. 8 is a diagram illustrating stereoscopic effects when the displayis switched in the case where the three-dimensional processing with areduced parallax is carried out. As shown in FIG. 8, when thephotographer has started the zoom control operation, the stereoscopiceffect of the three-dimensional display is reduced. Then, when thephotographer has ended the zoom control operation, the stereoscopiceffect is increased. In this case, the stereoscopic effect may beswitched gradually, as shown in FIG. 9.

The parallax between the first and second images G1 and G2 can also bereduced by reducing a distance between the imaging units 21A and 21B.That is, as shown in FIG. 10, reduction of the parallax between thefirst and second images G1 and G2 can be achieved by changing, when thezoom control operation is started, a baseline length K1 and aconvergence angle α1 between the imaging units 21A and 21B before thephotographer starts the zoom control operation to a baseline length K2and a convergence angle α2. The distance between the imaging units 21Aand 21B may be changed using a known mechanism.

Further, although the stereoscopic camera 1 is provided with the twoimaging units 21A and 21B and three-dimensional display is carried outusing the two images G1 and G2 in the above-described embodiment, theinvention is also applicable to a case where the stereoscopic camera 1is provided with three or more imaging units and three-dimensionaldisplay is carried out using three or more images.

One embodiment of the present invention has been described. Theinvention may also be implemented in the form of a program for causing acomputer to function as means corresponding to the display control unit28 and the three-dimensional processing unit 30 described above andcarry out the process as shown in FIG. 5. The invention may also beimplemented in the form of a computer-readable recording mediumcontaining such a program.

1. A three-dimensional imaging device comprising: two or more imagingunits for obtaining two or more images having a parallax therebetween byimaging a subject from different positions, the two or more imagingunits having an optical zoom function; a three-dimensional processingunit for applying three-dimensional processing for three-dimensionaldisplay to the two or more images; a display unit for carrying outvarious types of display including three-dimensional display of the twoor more images; and a display control unit for carrying outthree-dimensional display by reducing the parallax between the two ormore images or converting the three-dimensional display to atwo-dimensional display while the imaging units carry out a zoomoperation, wherein in a case where an object, which is displayed on thedisplay unit other than the images obtained through imaging of thesubject, is three-dimensionally displayed with being superposed on thethree-dimensionally displayed image, the display control unit carriesout three-dimensional display by reducing the parallax or converting thethree-dimensional display to a two-dimensional display of the objectwhile the imaging units carry out the zoom operations.
 2. Thethree-dimensional imaging device as claimed in claim 1, wherein thethree-dimensional processing unit carries out the three-dimensionalprocessing with a reduced parallax while the imaging units carry out thezoom operation.
 3. The three-dimensional imaging device as claimed inclaim 1, further comprising a notification unit for notifying that thethree-dimensional display with a reduced parallax or theatwo-dimensional display is being carried out.
 4. The three-dimensionalimaging device as claimed in claim 1, wherein the display control unitgradually reduces the parallax after the zoom operation is started untilthe parallax becomes 0 to finally carry out the a two-dimensionaldisplay.
 5. The three-dimensional imaging device as claimed in claim 1,wherein the display control unit gradually reduces the parallax afterthe zoom operation is started until the parallax becomes a predeterminedparallax to finally carry out the three-dimensional display with areduced parallax.
 6. A three-dimensional imaging method for use with athree-dimensional imaging device including two or more imaging units forobtaining two or more images having a parallax therebetween by imaging asubject from different positions, the two or more imaging units havingan optical zoom function, a three-dimensional processing unit forapplying three-dimensional processing for three-dimensional display tothe two or more images, and a display unit for carrying out varioustypes of display including three-dimensional display of the two or moreimages, the method comprising: carrying out three-dimensional display byreducing parallax between the two or more images or converting thethree-dimensional display to a two-dimensional display while the imagingunits carry out a zoom operation; and in a case where an object, whichis displayed on the display unit other than the images obtained throughimaging of the subject, is three-dimensionally displayed with beingsuperposed on the three-dimensionally displayed image, carrying outthree-dimensional display by reducing parallax or converting thethree-dimensional display to a two-dimensional display of the objectwhile the imaging units carry out the zoom operation.
 7. Anon-transitory computer-readable storage medium with an executableprogram for causing a computer to carry out a three-dimensional imagingmethod for use with a three-dimensional imaging device including two ormore imaging units for obtaining two or more images having a parallaxtherebetween by imaging a subject from different positions, the two ormore imaging units having an optical zoom function, a three-dimensionalprocessing unit for applying three-dimensional processing forthree-dimensional display to the two or more images, and a display unitfor carrying out various types of display including three-dimensionaldisplay of the two or more images, the program causing the computer tocarry out the procedure of: carrying out three-dimensional display byreducing parallax between the two or more images or converting thethree-dimensional display to a two-dimensional display while the imagingunits carry out a zoom operation; and in a case where an object, whichis displayed on the display unit other than the images obtained throughimaging of the subject, is three-dimensionally displayed with beingsuperposed on the three-dimensionally displayed image, carrying outthree-dimensional display by reducing parallax or converting thethree-dimensional display to a two-dimensional display of the objectwhile the imaging units carry out the zoom operation.